Image forming method

ABSTRACT

A method of forming a photographic image comprising imagewise exposing a silver halide color photographic material comprising a support having thereon a cyan color image forming layer, a magenta color image forming layer and an yellow color image forming layer, wherein the cyan color image forming layer in the photographic material contains silver halide emulsion grains having a silver chloride content of 95 mol % or more and containing substantially no silver iodide and contains a color sensitizing dye of the following general formula (I), ##STR1## wherein the terms are as defined in the specification and color developing the exposed material with a color developer, wherein the color developer has a chloride ion content of from 3.5×10 -2  to 1.5×10 -1  mol/liter and a bromide ion content of from 1.5×10 -5  to 1.0×10 -3  mol/liter.

This is a continuation of application No. 07/800,079 filed Nov. 29, 1991 now abandoned.

FIELD OF THE INVENTION

The present invention relates to an image forming method and, more precisely, to a method of forming a photographic image using a high silver chloride photographic material by rapid photographic processing, in which the material is hardly fogged and may be processed quite well with a fatigued color developer or by continuous processing while noticeably inhibition in the fluctuation of the sensitivity and gradation of the material being processed is achieved.

BACKGROUND OF THE INVENTION

Recently, photographic processing of color photographic materials has involved reducing the processing time to shorten the time for delivery of finished photo prints and have involved reducing the labor of photo laboratories. One method of shortening the time of the respective processing steps involves elevating the processing temperature in each step in general. In addition, other various methods of enhancing stirring of the processing solutions and adding various promoters to the processing bathes have been proposed.

Above all, to promote color development and/or reduce the amount of replenisher to be added in the development step, it is known to process a color photographic material containing a silver chloride emulsion, in place of a silver bromide emulsion or silver iodide emulsion which has heretofore been widely used. For instance, International Patent Laid-Open Application WO87-04534 describes a method of processing a silver halide color photographic material having a high silver chloride content or a so-called high silver chloride color photographic material with a color developer substantially containing neither sulfite ion nor benzyl alcohol.

However, it has been found that development of this type of material with an automatic color paper developing machine in accordance with the above-described method causes fluctuation of the photographic properties (especially, the minimum density) of the processed material and noticeable stain in the white background of the processed material.

Rapid development of a high silver chloride color photographic material thus involves a serious problem of fluctuation of the photographic properties of the processed material, and solution of the problem has been desired strongly.

One method of processing a high silver chloride color photographic material by rapid continuous processing with reducing fluctuation of the photographic properties (especially, fog) of the processed material involves use of an organic anti-foggant as disclosed in JP-A-58-95345 and 59-232342. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) However, the anti-fogging effect of the organic anti-foggant has been found to be insufficient so that use of the agent does not fully prevent an increase in the minimum density of the processed material using continuous processing. If a large amount of the agent is used in this method, it has further been found that such a large amount of the agent rather causes a decrease in the maximum density of the processed material.

JP-A-61-70552 discloses a method of processing a high silver chloride color photographic material by adding a replenisher to the developer in such an amount that the added replenisher does not cause overflow from the developer bath for the purpose of reducing the amount of the replenisher added in the method. JP-A-63-106655 discloses a method of developing a silver halide color photographic material having high silver chloride emulsion layer(s) with a color developer containing a hydroxylamine compound and a chloride, with the concentration of the chloride being more than a determined one, where the object is stabilizing the processing procedure.

However, it has been found that both of these prior art methods still result in fluctuation of the photographic properties of the processed material in continuous processing with an automatic developing machine. Anyway, the methods could not overcome the above-mentioned problem.

JP-A-2-96149 illustrates a continuous processing technique capable of noticeably decreasing the fluctuation in the minimum density of a processed silver halide photographic material in which a particular pentamethine cyanine dye is added to the material as a sensitizing dye and the chloride ion concentration and the bromide ion concentration in the color developer used are specifically defined. JP-A-2-96148 also illustrates another continuous processing technique for noticeably decreasing the fluctuation in the minimum density of a processed silver halide photographic material in which the silver bromide content in the silver halide emulsion of the material is specifically defined and the chloride ion concentration and the bromide ion concentration in the color developer used are specifically defined.

With this background, the present inventors conducted further investigations in this area and, as a result, they have found that the above-described techniques could be effectively used to noticeably decrease fluctuation in the minimum density of the processed photographic materials in continuous processing but they are not always sufficient to prevent fluctuation of the sensitivity and gradation of the processed photographic materials in continuous processing.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method of forming a photographic image with a high silver chloride photographic material by rapid photographic processing, in which the material is hardly fogged and may be processed well even with a fatigued color developer or by continuous processing with the fluctuation of the sensitivity and gradation of the material being processed being noticeably inhibited.

The object of the present invention is attained by a method of forming a photographic image comprising imagewise exposing a silver halide color photographic material comprising a support having thereon a cyan color image forming layer, a magenta color image forming layer and an yellow color image forming layer, wherein the cyan color image forming layer in the material contains silver halide emulsion grains having a silver chloride content of 95 mol % or more and having substantially no silver iodide and contains a color sensitizing dye of the following general formula (I), ##STR2## wherein Z₂₃ and Z₂₄ independently represent an atomic group necessary for forming a heterocyclic nucleus selected from the group consisting of a benzothiazole nucleus, a benzoselenazole nucleus, a naphthothiazole nucleus and a naphthoselenazole nucleus, which may optionally be substituted by at least one substituent selected from the group consisting of a halogen atom, an alkyl group, an alkoxy group, an aryl group and a hydroxyl group;

R₂₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group;

R₂₃ and R₂₄ independently represent a substituted or unsubstituted alkyl group;

X₂₁ represents an ion present for neutrality;

n₂₁ represents 0 or 1; and

when one of R₂₃ and R₂₄ forms an internal salt together with a quaternized nitrogen atom, n₂₁ is 0; and

color developing the exposed material with a color developer where the color developer has a chloride ion content of from 3.5×10⁻² to 1.5×10⁻¹ mol/liter and a bromide ion content of from 1.5×10⁻⁵ to 1.0×10⁻³ mol/liter.

DETAILED DESCRIPTION OF THE INVENTION

In formula (I), Z₂₃ and Z₂₄ each form a heterocyclic nucleus which may optionally be substituted by one or more substituents. Preferred examples of such substituents are a halogen atom such as fluorine, chlorine and bromine atoms; an alkyl group having 4 carbon atoms or less, such as methyl, ethyl and propyl groups; an alkoxy group having 4 carbon atoms or less, such as methoxy, ethoxy and propoxy groups; and an aryl group having 7 carbon atoms or less, such as phenyl and p-tolyl groups. R₂₅ is preferably a hydrogen atom; or a substituted or unsubstituted alkyl group having 8 carbon atoms or less including a carbon atom number of substituents, such as a methyl, ethyl, propyl, butyl or phenethyl group; or a substituted or unsubstituted aryl group having 7 carbon atoms or less including a carbon atom number of substituents, such as a phenyl group. Alkyl group represented by R₂₃ and R₂₄ preferably has 8 carbon atoms or less and more preferably 5 carbon atoms or less. R₂₃ and R₂₄ each are preferably a methyl, ethyl, n-propyl, i-propyl, 2-hydroxyehtyl, 4-hydroxybutyl, 2-acetoxyethyl, 3-acetoxypropyl, 2-methoxyethyl, 4-methoxybutyl, 2-carboxyethyl, 3-carboxypropyl, 2-(2-carboxyethoxy)ethyl, 2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl, 2-hydroxy-3-sulfopropyl, 2-(3-sulfopropoxy)ethyl, 2-acetoxy-3-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-[2-(3-sulfopropoxy)ethoxy]ethyl, 2-hydroxy-3-(3-sulfopropoxy)propyl, benzyl or phenethyl group.

Preferable substituents substituted on the alkyl group represented by R₂₅ include a phenyl group, and preferable substitutents substituted on the aryl group represented by R₂₅ include a halogen atom, a hydroxyl group, an alkyl group and an alkoxy group.

Preferable substituents substituted on the group represented by R₂₃ and R₂₄ include a sulfonic acid group, a carboxyl group, a hydroxyl group, an aryl group, an alkoxyl group, an acyl group and a combination thereof.

Of substituents on the nuclei in the formula, two alkyl groups may form a ring, for example, an acenaphthenothiazole ring or an acenaphthenoselenazole ring.

Specific examples of compounds of formula (I) are described below, but, the present invention is not to be construed as being limited to these examples.

       Compound          Mother Skeleton No. X Y A A' R.sub.25 R.sub.23      R.sub.24 X.sub.21 n.sub.21       ##STR3##       I-1I-2I-3I-4I-5I-6 S""""" S""""" -------- ---- ------------       ##STR4##       C.sub.2 H.sub.5"(CH.sub.2).sub.3 SO.sub.3.sup.⊖C.sub.2       H.sub.5"(CH.sub.2).sub.3 SO.sub.3.sup.⊖ C.sub.2       H.sub.5(CH.sub.2).sub.3 SO.sub.3.sup.⊖"C.sub.2       H.sub.5(CH.sub.2).sub.3       SO.sub.3.sup.⊖" I.sup.⊖--H.sup.⊕       NEt.sub.3I.sup.⊖--H.sup.⊕ NEt.sub.3 101101       ##STR5##       I-7I-8I-9I-10I-11I-12I-13I-14I-15I-16I-17 S"""""S"""" S"""""Se""""      5-Cl5-OCH.sub.35-OCH.sub.3 -6-CH.sub.35-Cl5-OCH.sub.35-OCH.sub.3      -6-CH.sub.3----5-Cl"5-CH.sub.3 ----------------------       ##STR6##       C.sub.2 H.sub.5"""""C.sub.2 H.sub.5"""" (CH.sub.2).sub.3       SO.sub.3.sup.⊖"""""C.sub.2 H.sub.5(CH.sub.2).sub.3       SO.sub.3.sup.⊖C.sub.2 H.sub.5(CH.sub.2).sub.3       SO.sub.3.sup.⊖C.sub.2       H.sub.5 ------------I.sup.⊖--I.sup.⊖--I.sup.⊖   0      00       ##STR7##       I-18I-19I-20I-21I-22I-23I-24I-25 S""""""" Se""""""" 5-CH.sub.35-OCH.sub.      35-OH"5,6-diCH.sub.35-Cl5-OCH.sub.35-OCH.sub.3       -6-CH.sub.3 ---------- ------       ##STR8##       C.sub.2 H.sub.5""""""" (CH.sub.2).sub.3 SO.sub.3.sup.⊖"C.sub.2      H.sub.5(CH.sub.2).sub.3       SO.sub.3.sup.⊖"""" ----I.sup.⊖---------- 00100000       ##STR9##       I-26I-27I-28I-29I-30I-31I-32I-33I-34 S""Se""""" S""Se""""" 5-Cl5-OCH.sub      .35-OCH.sub.3--5-Cl5-CH.sub.35-OH5-OCH.sub.35,6-diCH.sub.3 ----5'-CH.sub.      3------------       ##STR10##       (CH.sub.2).sub.3 SO.sub.3.sup.⊖""C.sub.2       H.sub.5 """"" (CH.sub.2).sub.3 SO.sub.3.sup.⊖""C.sub.2       H.sub.5 """"" H.sup.⊕ NEt.sub.3""I.sup.⊖""""" 111111111       ##STR11##       I-35I-36I-37I-38I-39I-40I-41I-42 Se""""""" Se""""""" 5-Cl"--5-Cl5-CH.sub      .35-OH5-OCH.sub.35,6-diCH.sub.3 --5'-CH.sub.3------------       ##STR12##       C.sub.2 H.sub.5"(CH.sub.2).sub.3       SO.sub. 3.sup.⊖""""" (CH.sub.2).sub.3       SO.sub.3.sup.⊖""""""" ----H.sup.⊕ NEt.sub.3""""" 00111111       ##STR13##       I-43 S S -- -- C.sub.2 H.sub.5 C.sub.2 H.sub.5  C.sub.2 H.sub.5      I.sup.⊖ 1

The color sensitizing dye of formula (I) can be incorporated into a silver halide emulsion of the photographic material of the present invention by directly dispersing the dye in the emulsion or, alternatively, it may first be dissolved in a single solvent comprising water, methanol, ethanol, propanol, methyl cellosolve or 2,2,3,3-tetrafluoropropanol or a mixed solvent comprising two or more of them to form a dye solution and the resulting dye solution may be added to the emulsion. In addition, the dye may be dissolved in an aqueous solution along with an acid or base in accordance with the techniques as described in JP-B-44-23389, 44-27555 and 57-22089 (the term "JP-B" as used herein means an "examined Japanese patent publication"); or it may be formed into an aqueous solution or a colloidal dispersion in the presence of a surfactant in accordance with the technique as described in U.S. Pat. No. 4,006,025; and the resulting aqueous solution or colloidal dispersion may be added to the emulsion. The dye may also be dissolved in a substantially water-immiscible solvent, such as phenoxyethanol, then dispersed in water or a hydrophilic colloid, and the resulting dispersion may be added to the emulsion. The dye may directly be dispersed in a hydrophilic colloid and the resulting dispersion may be added to the emulsion, in accordance with the procedure described in JP-A-53-102733 and 58-105141.

The time of adding the dye of formula (I) to the emulsion is not specifically limited and the dye may be added thereto at any stage of forming the emulsion or may be added thereto just before coating. For instance, the dye may be added to the emulsion at the same time a chemical sensitizer is added to simultaneously achieve color sensitization and chemical sensitization of the emulsion, in accordance with the technique described in U.S. Pat. No. 4,225,666; or it may be added to the emulsion prior to chemical sensitization, in accordance with the technique described in JP-A-58-113928; or it may be added to the emulsion before completion of formation of the silver halide grains to achieve color sensitization of the grains. Portionwise addition of the color sensitizing dye of formula (I) may also be possible in accordance with the manner described in U.S. Pat. No. 4,225,666. For instance, some of the dye is first added to the emulsion prior to chemical sensitization thereof and the remainder is then added thereto after chemical sensitization of the emulsion. Moreover, the dye may be added during formation of silver halide grains of the emulsion, for example, in accordance with the method illustrated in U.S. Pat. No. 4,183,756.

The amount of the color sensitizing dye of formula (I) present in the emulsion of the photographic material of the present invention is preferably from 5×10⁻⁶ to 5×10⁻³ mol, more preferably from 2×10⁻⁵ to 1×10⁻³ mol, per mol of silver halide in the emulsion.

The halogen composition of the silver halide emulsion grains of the photographic material of the present invention are grains of silver chlorobromide where 95 mol % or more of the total grains are silver chloride grains, or pure silver chloride grains, and silver chlorobromide and silver chloride grains are substantially free from silver iodide. Silver chlorobromide or silver chloride grains which are substantially free from silver iodide mean that the grains have a silver iodide content of 1.0 mol % or less. Preferably, the silver halide grains of the high silver halide emulsion of the present invention are silver chlorobromide grains having a silver chloride content of 98 mol % or more of the total silver halide composing silver halide grains or are silver chloride grains, which contain substantially no silver iodide. Most preferably, the silver halide grains of the high silver halide emulsion of the present invention are silver chlorobromide grains having a silver chloride content of 99 mol % or more of the total silver halide composing silver halide grains or are silver chloride grains, which contain substantially no silver iodide.

The silver halide emulsion grains of the photographic material of the present invention preferably have a silver bromide localized phase in an amount of more than 10 mol % as silver bromide. The position of such a high silver bromide localized phase in the grains is preferably near the surface of the grains for the purpose of effectively displaying the effect of the present invention and in view of the pressure resistance of the material achieved and the composition dependence of the processing solution used in processing the material. The position near the surface of the silver halide grain means a depth of 1/5 or less of the grain thickness from the outermost surface of the grain. More preferably, the high silver bromide localized phase is at a depth of 1/10 or less of the grain size from the outermost surface of the grain. As the most preferred example of the position of the high silver bromide localized phase, a silver bromide localized phase having a silver bromide content of more than 10 mol % is on the corners of cubic or tetradecahedral silver chloride grains formed by epitaxial growth.

The silver bromide content in the high silver bromide localized phase must be more than 10 mol %, but if the silver bromide content is too high in this phase, the phase often causes desensitization of the photographic material when a pressure is imparted to the material or the sensitivity and gradation of the material greatly vary because of changes in the composition of the processing solution used in processing the material. Such a silver bromide localized phase with too high a silver bromide content often results in unfavorable properties in the photographic material. In view of these points, the silver bromide content in the high silver bromide localized phase is preferably from 10 to 60 mol %, most preferably from 20 to 50 mol %. The silver bromide content of the high silver bromide localized phase may be analyzed by an X-ray diffraction method (for example, as described in Lectures of New Experimental Chemistry, No. 6, Structure Analyses, edited by Nippon Chemical Society and published by Maruzen Publishing Co., Japan). Preferably, the high silver bromide localized phase has a silver content of from 0.1 to 20%, more preferably from 0.5 to 10%, of the total silver content of the silver halide grains with the localized phase.

The interface between the high silver bromide localized phase and the other phase in the silver halide grain of the photographic material of the present invention may have a distinct phase boundary or, alternatively, may have a region where the halogen composition gradually varies therebetween.

Various methods may be employed for forming such a high silver bromide localized phase. For instance, a soluble silver salt and soluble halides can be reacted in a single jet method or a double jet method to form the desired localized phase. In addition, a halogen conversion method in which already formed silver halide grains are converted into those having a lower solubility product may also be employed for forming the intended localized phase. More preferably, for conveniently achieving the effect of the present invention, the high silver bromide localized phase is formed in such a way that cubic or tetradecahedral host silver halide grains are blended and ripened with fine silver halide grains having a smaller mean grain size than the host grains and having a higher silver bromide content than the host grains to thereby form a high silver bromide phase on the silver halide host grains.

The silver halide emulsions of the photographic material of the present invention are preferably chemically sensitized. For chemical sensitization of the emulsions, for example, sulfur sensitization, selenium sensitization, reduction sensitization or gold sensitization may be employed. Sulfur sensitization is especially preferred.

Sulfur-containing compounds capable of reacting with an active gelatin or silver, such as thiosulfates, thioureas, mercapto compounds and rhodanines can be used for chemically sensitizing the silver halide emulsions of the present invention with sulfur. Specific examples of suitable sulfur-containing compounds are described in U.S. Pat. Nos. 1,574,944, 2,278,947, 2,410,689, 2,728,668 and 3,656,955.

The silver halide grains of the photographic material of the present invention may be those having a (100) plane as the outer surface or those having a (111) plane as the outer surface or those having both planes as the outer surface. In addition, they may also be those having a higher order plane. Preferably, the grains are cubic or tetradecahedral grains essentially having a (100) plane.

The size of the silver halide grains of the photographic material of the present invention may vary over a wide range. Preferably, the grains have a mean grain size of from 0.1 μm to 1.5 μm. The grain size distribution of the grains may be either polydispersed or monodispersed. Preferably, the grains are monodispersed grains. The grain size distribution of the grains indicating the degree of the monodispersibility of the grains is such that the ratio (s/d) of the statistical standard deviation (s) to the mean grain size (d) is 0.2 or less, more preferably 0.15 or less. It is also preferred to use a mixture comprising two or more kinds of monodispersed emulsions.

The silver halide emulsion grains of the photographic material of the present invention preferably contain an iridium compound. Examples of usable iridium compounds are hexachloroiridates(III) or (IV), hexamineiridates(III) or (IV) and trioxalatoiridates(III) or (IV).

In particular, it is preferred to incorporate an iridium compound in the high silver bromide localized phase, or to form the localized phase in the presence of an iridium compound. Formation of the localized phase in the presence of an iridium compound may be effected by adding an iridium compound to the silver halide emulsion simultaneously with, or just before, or just after addition of silver or halogen for forming the localized phase to the emulsion. Where the high silver bromide localized phase is formed by blending host silver halide grains and other fine silver halide grains having a smaller mean grain size and a higher silver bromide content than the host grains followed by ripening the resulting blend, it is preferred to previously incorporate an iridium compound into the fine silver halide grains having a higher silver bromide content.

The amount of the iridium compound to be employed in the above-described case is preferably from 10⁻⁹ mol to 10⁻⁶ mol, most preferably from 10⁻⁸ mol to 10⁻⁶ mol, per mol of silver halide in the emulsion.

To improve the sharpness of the image formed on the photographic material of the present invention, it is preferred to incorporate a dye capable of being decolored by the photographic processing, as described in European Patent 0,337,490A2 (especially oxonole dyes), into the hydrophilic colloid layer of the material in such an amount that the optical reflection density of the material at 680 nm is 0.70 or more, or to incorporate titanium oxide surface-treated with a di-hydric to tetra-hydric alcohol (e.g., trimethylolethane) into the water-proof resin layer of the support of the material in an amount of 12% by weight or more, more preferably 14% by weight or more.

The photographic material of the present invention preferably contains a color image preservability improving compound, for example, a compound as described in European Patent 0,277,589A2, along with couplers.

Incorporation of such a color image preservability improving compound into the material along with a pyrazoloazole coupler is preferred.

Specifically, the single or combined incorporation of a compound (F) capable of chemically binding with the aromatic amine developing agent remaining in the photographic material after color development thereof to form a chemically inert and substantially colorless compound and/or a compound (G) capable of chemically binding with the oxidation product of an aromatic amine developing agent remaining in the photographic material after color development thereof to form a chemically inert and substantially colorless compound into the photographic material of the present invention is preferred for the purpose of preventing formation of color dyes by reaction of the color developing agent or the oxidation product thereof remaining in the photographic material and couplers in the material during storage of the processed material which results in the formation of stains in the processed material during storage thereof and also preventing any other harmful side effect of the remaining developing agent and the oxidation product thereof.

The photographic material of the present invention also preferably contains a microbiocide, such as the one as described in JP-A-63-271247, for the purpose of preventing propagation of various fungi and bacteria in the hydrophilic colloid layer of the processed material which would deteriorate the image formed on the material.

Suitable supports of the photographic material of the present invention include a white polyester support or a support having a white pigment-containing layer on the side on which the silver halide emulsion layers are coated may be employed. In order to improve the sharpness of the image to be formed, it is preferred to provide an anti-halation layer on the support on either of the side on which the silver halide emulsion layers are coated or the opposite side thereto. In particular, it is preferred for the transmission density of the support to be within the range of from 0.35 to 0.8, in order that the the photographic material of the present invention be may seen either with reflected light or transmitted light.

The photographic material of the present invention may be exposed either with visible light or with infrared light. For exposure of the material, either low intensity exposure or high intensity short-time exposure may be employed. In particular, in the latter case, a laser scanning exposure system is preferred where the exposure time is shorter than 10⁻⁴ second per pixel.

A band stop filter described in U.S. Pat. No. 4,880,726 is preferably used for exposure of the photographic material of the present invention. Using such a filter allows rays causing color mixture to be removed so that the color reproducibility of the exposed material is improved noticeably.

The exposed photographic material is color-developed and then preferably bleach-fixed for the purpose of effecting rapid processing. In particular, when the high silver chloride emulsion(s) disclosed above is used, the pH of the bleach-fixing solution is preferably about 6.5 or less, especially preferably about 6 or less, for the purpose of promoting desilvering of the material.

The silver halide emulsions and other elements (e.g., additives, etc.) of the photographic material of the present invention, the photographic layers of the material (e.g., arrangement of layers), and methods of processing the material and additives usable in the processing methods are described in the following patent publications, especially in European Patent 0,355,660A2 (corresponding to Japanese Patent Application No. 1-107011) and are preferably employed.

    __________________________________________________________________________     Photographic Elements                                                                      JP-A-62-215272                                                                               JP-A-2-33144  EP 0,355,660A2                         __________________________________________________________________________     Silver Halide                                                                              From page 10, right upper                                                                    From page 28, right upper                                                                    From page 45, line 53 to               Emulsions   column, line 6 to page 12,                                                                   column, line 16 to page 29,                                                                  page 47, line 3; and page 47,                      left lower column, line 5;                                                                   right lower column, line 11;                                                                 lines 20 to 22                                     and from page 12, right                                                                      and page 30, lines 2 to 5                                        lower column, line 4 to page                                                   13, left upper column, line                                                    17                                                                 Silver Halide Solvents                                                                     Page 12, left lower column,                                                                  --            --                                                 lines 6 to 14; and from page                                                   13, left upper column, line                                                    3 from below to page 18,                                                       left lower column, last line                                       Chemical Sensitizers                                                                       Page 12, from left lower                                                                     Page 29, right lower column,                                                                 Page 47, lines 4 to 9                              column, line 3 from below to                                                                 line 12 to last line                                             right lower column, line 5                                                     from below; and from page                                                      18, right lower column, line                                                   1 to page 22, right upper                                                      column, line 9 from below                                          Spectral Sensitizers                                                                       From page 22, right upper                                                                    Page 30, left upper column,                                                                  Page 47, lines 10 to 15                (Spectral Sensitizing                                                                      column, line 8 from below to                                                                 lines 1 to 13                                        Methods)    page 38, last line                                                 Emulsion Stabilizers                                                                       From page 39, left upper                                                                     Page 30, from left upper                                                                     Page 47, lines 16 to 19                            column, line 1 to page 72,                                                                   column, line 14 to right                                         right upper column, last                                                                     upper column, line 1                                             line                                                               Development Promoters                                                                      From page 72, left lower                                                                     --            --                                                 column, line 1 to page 91,                                                     right upper column, line 3                                         Color Couplers (Cyan,                                                                      From page 91, right upper                                                                    From page 3, right upper                                                                     Page 4, lines 15 to 27; from           Magenta and Yellow                                                                         column, line 4 to page 121,                                                                  column, line 14 to page 18,                                                                  page 5, line 30 to page 8,             Couplers)   left upper column, line 6                                                                    left upper column, last                                                                      last line; page 45, lines 29                                     line; and from page 30,                                                                      to 31; and from page 47, line                                    right upper column, line 6                                                                   23 to page 63, line 50                                           to page 35, right lower                                                        column, line 11                                      Coloring Enhancers                                                                         From page 121, left upper                                                                    --            --                                                 column, line 7 to page 125,                                                    right upper column, line 1                                         Ultraviolet Absorbents                                                                     From page 125, right upper                                                                   From page 37, right lower                                                                    Page 65, lines 22 to 31                            column, line 2 to page 127,                                                                  column, line 14 to page 38,                                      left lower column, last line                                                                 left upper column, line 11                           Anti-fading Agents                                                                         From page 127, right lower                                                                   From page 36, right upper                                                                    From page 4, line 30 to                (Color Image                                                                               column, line 1 to page 137,                                                                  column, line 12 to page 37,                                                                  page 5, line 23; from page 29,         Stabilizers)                                                                               left lower column, line 8                                                                    left upper column, line 19                                                                   line 1 to page 45, line 25;                                                    page 45, lines 33 to 40; and                                                   page 65, lines 2 to 21                 High Boiling Point                                                                         From page 137, left lower                                                                    From page 35, right lower                                                                    Page 64, lines 1 to 51                 and/or Low Boiling                                                                         column, line 9 to page 144,                                                                  column, line 14 to page 36,                          Point Organic Solvents                                                                     right upper column, last                                                                     left upper column, line 4                                        line          from below                                           Dispersing Methods of                                                                      From page 144, left lower                                                                    From page 27, right lower                                                                    From page 63, line 51 to               Photographic Additives                                                                     column, line 1 to page 146,                                                                  column, line 10 to page 28,                                                                  page 64, line 56                                   right upper column, line 7                                                                   left upper column, last line;                                                  and from page 35, right                                                        lower column, line 12, to                                                      page 36, right upper column,                                                   line 7                                               Hardening Agents                                                                           From page 146, right upper                                                                   --            --                                                 column, line 8 to page 155,                                                    left lower column, line 4                                          Developing Agent                                                                           Page 155, from left lower                                                                    --            --                                     Precursors  column, line 5 to right                                                        lower column, line 2                                               Development Inhibitor                                                                      Page 155, right lower                                                                        --            --                                     Releasing Compounds                                                                        column, lines 3 to 9                                               Supports    From page 155, right lower                                                                   From page 38, right upper                                                                    From page 66, line 29 to                           column, line 19 to page 156,                                                                 column, line 18 to page 39,                                                                  page 67, line 13                                   left upper column, line 14                                                                   left upper column, line 3                            Constitution of                                                                            Page 156, from left upper                                                                    Page 28, right upper column,                                                                 Page 45, lines 41 to 52                Photographic Layers                                                                        column, line 15 to right                                                                     lines 1 to 15                                                    lower column, line 14                                              Dyes        From page 156, right lower                                                                   Page 38, from left upper                                                                     Page 66, lines 18 to 22                            column, line 15 to page 184,                                                                 column, line 12 to right                                         right lower column, last                                                                     upper column, line 7                                             line                                                               Color Mixing                                                                               From page 185, left upper                                                                    Page 36, right lower column,                                                                 From page 64, line 57 to               Preventing Agents                                                                          column, line 1 to page 188,                                                                  lines 8 to 11 page 65, line 1                                    right lower column, line 3                                         Gradation Adjusting                                                                        Page 188, right lower                                                                        --            --                                     Agents      column, lines 4 to 8                                               Stain Inhibitors                                                                           From page 188, right lower                                                                   Page 37, from left upper                                                                     From page 65, line 32 to                           column, line 9 to page 193,                                                                  column, last line to right                                                                   page 66, line 17                                   right lower column, line 10                                                                  lower column, line 13                                Surfactants From page 201, left lower                                                                    From page 18, right upper                                                                    --                                                 column, line 1 to page 210,                                                                  column, line 1 to page 24,                                       right upper column, last one                                                                 right lower column, last                                                       line; and page 27, from left                                                   lower column, line 10 from                                                     below to right lower                                                           column, line 9                                       Fluorine-containing                                                                        From page 210, left lower                                                                    From page 25, left upper                                                                     --                                     Compounds (as antistatic                                                                   column, line 1 to page 222,                                                                  column, line 1 to page 27,                           agents, coating aids,                                                                      left lower column, line 5                                                                    right lower column, line 9                           lubricants, and anti-                                                          blocking agents)                                                               Binders (hydrophilic                                                                       From page 222, left lower                                                                    Page 38, right upper column,                                                                 Page 66, lines 23 to 28                colloids)   column, line 6 to page 225,                                                                  lines 8 to 18                                                    left upper column, last line                                       Tackifiers  From page 225, right upper                                                                   --            --                                                 column, line 1 to page 227,                                                    right upper column, line 2                                         Antistatic Agents                                                                          From page 227, right upper                                                                   --            --                                                 column, line 3 to page 230,                                                    left upper column, line 1                                          Polymer Latexes                                                                            From page 230, left upper                                                                    --            --                                                 column, line 2 to page 239,                                                    last line                                                          Mat Agents  Page 240, from left upper                                                                    --            --                                                 column, line 1 to right                                                        upper column, last line                                            Photographic Processing                                                                    From page 3, right upper                                                                     From page 39, left upper                                                                     From page 67, line 14 to               Methods (Processing                                                                        column, line 7 to page 10,                                                                   column, line 4 to page 42,                                                                   page 69, line 28                       steps and additives)                                                                       right upper column, line 5                                                                   left upper column, last line                         __________________________________________________________________________      Notes:                                                                         The specification of JPA-62-215272 cited above is as amended by amendment      filed on March 16, 1987.                                                 

The so-called short-wave type yellow couplers as described in JP-A-63-231451, 63-123047, 63-241547, 1-173499, 1-213648 and 1-250944 are also preferably employed as yellow couplers, in addition to those described above.

3-Hydroxypyridine cyan couplers as described in European Patent 0,333,185A2 (Especially, 2-equivalent couplers by adding a chlorinated releasable group to the illustrated 4-equivalent Coupler (42), as well as the illustrated Couplers (6) and (9) are preferred.), and the cyclic active methylene cyan couplers as described in JP-A-64-32260 (Especially, Couplers Nos. 3, 8 and 34 specifically illustrated therein are preferred.) are also preferably employed as cyan couplers, in addition to diphenylimidazole cyan couplers described in the above-mentioned JP-A-2-33144.

In accordance with the present invention, the color developer to be used in processing the photographic material needs to contain chloride ion in an amount of from 3.5×10⁻² to 1.5×10⁻¹ mol/liter, preferably from 4×10⁻² to 1×10⁻¹ mol/liter. If the chloride ion concentration in the color developer is more than 1.5×10⁻¹ mol/liter, development of the material therewith is delayed or retarded so that the maximum density of the image formed is disadvantageously low. On the contrary, however, if the chloride ion concentration is less than 3.5×10⁻² mol/liter, fluctuation of the photographic properties of the processed material, especially fluctuation in the minimum density of the formed image, in continuous processing is disadvantageously large.

In addition, in accordance with the present invention, the color developer also needs to contain bromide ion in an amount of from 1.5×10⁻⁵ to 1.0×10⁻³ mol/liter, preferably from 2×10⁻⁵ to 5×10⁻⁴ mol/liter. If the bromide ion concentration in the developer is more than 1.0×10⁻³ mol/liter, development of the material therewith is delayed or retarded so that the maximum density of the formed image and sensitivity are disadvantageously low. On the contrary, however, if the bromide ion concentration is less than 1.5×10⁻⁵ mol/liter, fluctuation of the photographic properties of the processed material, especially fluctuation in the minimum density of the formed image, in continuous processing is not effectively prevented.

The chloride ion and bromide ion may be directly added to the color developer, or they may be dissolved from the photographic material being processed with the color developer.

In the former case where the ions are directly added to the color developer, a chloride ion-donating material is added thereto, which includes, for example, sodium chloride, potassium chloride, ammonium chloride, nickel chloride, magnesium chloride, manganese chloride, calcium chloride and cadmium chloride. Of them, sodium chloride and potassium chloride are preferred.

The ions may also be added to the developer in the form of a salt of a brightening agent to be added thereto. Examples of bromide ion-donating materials usable in the present invention are mentioned sodium bromide, potassium bromide, ammonium bromide, lithium bromide, calcium bromide, magnesium bromide, manganese bromide, nickel bromide, cadmium bromide, cerium bromide and thallium bromide. Of them, preferred are potassium bromide and sodium bromide.

In the latter case where the ions are dissolved out into the color developer from the photographic material being processed therein, both the chloride ion and the bromide ion may be derived from the silver halides in the emulsions in the material or may also be derived from any other layers in the material.

The present invention is explained in more detail by way of the following examples, which, however, are not intended to restrict the scope of the present invention. Unless otherwise indicated herein, all parts, percents, ratios and the like are by weight.

EXAMPLE 1

32 g of a lime-processed gelatin was added to 1000 cc of distilled water and dissolved at 40° C., 3.3 g of sodium chloride was added thereto, and the temperature of the resulting solution was increased to 60° C. To the solution was added 1.8 cc of an aqueous 1% solution of N,N'-dimethylimidazolidine-2-thione. Next, a solution of 32.0 g of silver nitrate dissolved in 200 cc of distilled water and a solution of 11.0 g of sodium chloride dissolved in 200 cc of distilled water were added, with stirring, to the previously prepared solution over a period of 14 minutes at 60° C. Further, a solution of 128.0 g of silver nitrate dissolved in 560 cc of distilled water and a solution of 44.0 g of sodium chloride dissolved in 560 cc of distilled water were added thereto, with stirring, over a period of 40 minutes at 60° C. The resulting emulsion was desalted and washed with water at 40° C., 90.0 g of a lime-processed gelatin was added thereto, and sodium chloride and sodium hydroxide were added thereto whereby the pAg and pH of the emulsion were adjusted to be 7.5 and 6.5, respectively. Subsequently, the emulsion was optimally sulfur-sensitized with triethylthiourea at 50° C. The silver chloride emulsion thus obtained was designated Emulsion (A).

32 g of a lime-processed gelatin was added to 1000 cc of distilled water and dissolved at 40° C., 3.3 g of sodium chloride was added thereto, and the temperature of the resulting solution was increased to 60° C. To the solution was added 2.0 cc of an aqueous 1% solution of N,N'-dimethylimidazolidine-2-thione. Next, a solution of 32.0 g of silver nitrate dissolved in 200 cc of distilled water and a solution of 10.9 g of sodium chloride and 0.22 g of potassium bromide dissolved in 200 cc of distilled water were added, with stirring, to the previously prepared solution over a period of 15 minutes at 60° C. Further, a solution of 128.0 g of silver nitrate dissolved in 560 cc of distilled water and a solution of 43.6 g of sodium chloride and 0.90 g of potassium bromide dissolved in 560 cc of distilled water were added thereto, with blending, over a period of 40 minutes at 60° C. The resulting emulsion was desalted and washed with water at 40° C., 90.0 g of a lime-processed gelatin was added thereto, and sodium chloride and sodium hydroxide were added thereto whereby the pAg and pH of the emulsion were adjusted to 7.5 and 6.5, respectively. Subsequently, the emulsion was optimally sulfur-sensitized with triethylthiourea at 50° C. The silver chlorobromide emulsion (having a silver bromide content of 1 mol %) thus obtained was designated Emulsion (B).

32 g of a lime-processed gelatin was added to 1000 cc of distilled water and dissolved at 40° C., 3.3 g of sodium chloride was added thereto, and the temperature of the resulting solution was increased to 60° C. To the solution was added 2.4 cc of an aqueous 1% solution of N,N'-dimethylimidazolidine-2-thione. Next, a solution of 32.0 g of silver nitrate dissolved in 200 cc of distilled water and a solution of 10.2 g of sodium chloride and 1.57 g of potassium bromide dissolved in 200 cc of distilled water were added, with stirring, to the previously prepared solution over a period of 20 minutes at 60° C. Further, a solution of 128.0 g of silver nitrate dissolved in 560 cc of distilled water and a solution of 41.0 g of sodium chloride and 6.28 g of potassium bromide dissolved in 560 cc of distilled water were added thereto, with stirring, over a period of 60 minutes at 60° C. The resulting emulsion was desalted and washed with water at 40° C., 90.0 g of a lime-processed gelatin was added thereto, and sodium chloride and sodium hydroxide were added thereto whereby the pAg and pH of the emulsion were adjusted to 7.5 and 6.5, respectively. Subsequently, the emulsion was optimally sulfur-sensitized with triethylthiourea at 50° C. The silver chlorobromide emulsion (having a silver bromide content of 7 mol %) thus obtained was designated Emulsion (C).

Still another silver chlorobromide emulsion was prepared in the same manner as in preparation of Emulsion (A), except that an emulsion of ultra-fine silver bromide grains (having a grain size of 0.05 μm) was added to the intermediate emulsion, prior to sulfur-sensitization thereof, in an amount of 1.0 mol %, with respect to the silver chloride present, of silver bromide, then the resulting emulsion blend was ripened for 15 minutes at 50° C. and thereafter subjected to optimal sensitization. The thus prepared silver chlorobromide emulsion was Emulsion (D).

The grain shape, grain size and grain size distribution of each of the four Emulsions (A) through (D) thus prepared were determined using their electromicrophotographs. The grain size was represented by the mean value of the diameter of a circle equivalent to the projected area of each grain; and the grain size distribution was represented by the value obtained by dividing the standard deviation of the grain size by the mean grain size. All four kinds of Emulsions (A) through (D) contained cubic grains having a mean grain size of 0.54 μm and a grain size distribution of 0.09.

Comparing the electromicrophotograph of Emulsion (D) to which ultra-fine silver bromide grains had been added and that of Emulsion (A) to which no ultra-fine silver bromide grains had been added, the corners of the cubic grains of the Emulsion (D) were found to be sharper than those of Emulsion (A). X-ray diffraction analysis of Emulsion (D) showed a weak diffraction in the part corresponding to a silver bromide content of from 10 mol % to 40 mol %. From the facts, Emulsion (D) was determined to contain cubic silver chlorobromide grains having a silver bromide localized phase with a silver bromide content of from 10 mol % to 40 mol % on the corners of the cubic silver chloride grain (host grain), the localized phase having grown by epitaxial growth.

One surface of a paper support, both surfaces of which had been laminated with polyethylene, was corona-discharged, a gelatin subbing layer containing sodium dodecylbenzenesulfonate was formed on the support, and plural photographic layers described below were formed thereon. Accordingly, a multi-layer color photographic paper (Sample No. 1) having the layer constitution described below was prepared.

Preparation of Coating Composition for First Layer

27.2 cc of ethyl acetate, 4.1 g of solvent (Solv-3) and 4.1 g of solvent (Solv-7) were added to 19.1 g of yellow coupler (ExY), 4.1 g of color image stabilizer (Cpd-1) and 0.7 g of color image stabilizer (Cpd-7), and dissolved. The resulting solution was added to 185 cc of an aqueous 10% gelatin solution containing 8 cc of sodium dodecylbenzenesulfonate and emulsified and dispersed using an ultrasonic homogenizer. The resulting dispersion was blended with a silver chlorobromide emulsion (containing silver halide cubic grains having a mean grain size of 0.80 μm and a silver bromide content of 0.5 mol % as a silver bromide localized phase partially on the surface of the grain, and containing blue-sensitizing dyes (A) and (B) each in an amount of 2×10⁻⁴ mol per mol of silver halide), to prepare a coating composition for the First Layer.

50.0 cc of ethyl acetate and 14.0 g of solvent (Solv-6) were added to 32.0 g of cyan coupler (ExC), 3.0 g of color image stabilizer (Cpd-2), 2.0 g of color image stabilizer (Cpd-4), 18.0 g of color image stabilizer (Cpd-6), 40.0 g of color image stabilizer (Cpd-7) and 5.0 g of color image stabilizer (Cpd-8), and dissolved. The resulting solution was added to 500 cc of an aqueous 20% gelatin solution containing 8 cc of sodium dodecylbenzenesulfonate and emulsified and dispersed using an ultrasonic homogenizer. The resulting dispersion was blended with Emulsion (A) (silver chloride emulsion) to prepare a coating composition for the Fifth Layer.

Other coating compositions for the Second to Fourth Layers, Sixth Layer and Seventh Layer were prepared in the same manner as in preparation of the coating composition for the Fifth Layer mentioned above. 1-Hydroxy-3,5-dichloro-s-triazine sodium salt was added to each layer as a gelatin hardening agent for each layer.

Additionally, Cpd-10 and Cpd-11 below were added to each layer, the total amount of additive Cpd-10 being 25.0 mg/m² and that of additive Cpd-11 being 50.0 mg/m².

The following color sensitizing dyes were added to each layer.

Sensitizing Dye (A) to Blue-Sensitive Emulsion Layer ##STR14## Sensitizing Dye (B) to Blue-Sensitive Emulsion Layer ##STR15## Sensitizing Dye (C) to Green-Sensitive Emulsion Layer ##STR16## (4.0×10⁻⁴ mol per mol of silver halide to large grain size emulsion; 5.6×10⁻⁴ mol per mol of silver halide to small grain size emulsion) Sensitizing Dye (D) to Green-Sensitive Emulsion Layer ##STR17## (7.0×10⁻⁵ mol per mol of silver halide to large grain size emulsion; and 1.0×10⁻⁵ mol per mol of silver halide to small grain size emulsion) Sensitizing Dye (S-1) to Red-Sensitive Emulsion Layer ##STR18## (8.0×10⁻⁵ mol per mol of silver halide)

To the red-sensitive emulsion layer was added the following compound in an amount of 2.6×10⁻³ mol per mol of silver halide. ##STR19##

To the blue-sensitive emulsion layer, the green-sensitive emulsion layer and the red-sensitive emulsion layer was added 1-(5-methylureidophenyl)-5-mercapto-tetrazole in an amount of 8.5×10⁻⁵ mol, 7.7×10⁻⁴ mol and 2.5×10⁻⁴ mol, respectively, per mol of silver halide.

To the blue-sensitive emulsion layer and the green-sensitive emulsion layer was added 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene in an amount of 1×10⁻⁴ mol and 2×10⁻⁴ mol, respectively, per mol of silver halide.

The following dyes were added to the emulsion layers for anti-irradiation, each in the amount as shown in the parentheses. ##STR20##

Constitution of Layers

The compositions of the layers are shown below. The number indicates the amount coated in units of g/m². The amount of silver halide emulsion coated is represented by the amount of silver therein.

    __________________________________________________________________________     Support:                                                                       Polyethylene-Laminated Paper                                                   (containing white pigment (TiO.sub.2) and bluish dye (ultramarine) in the      polyethylene below                                                             the First Layer)                                                               First Layer (Blue-sensitive Emulsion Layer):                                   Above-mentioned Silver Bromochloride Emulsion                                                                            0.30                                 Gelatin                                   1.86                                 Yellow Coupler (ExY)                      0.82                                 Color Image Stabilizer (Cpd-1)            0.19                                 Solvent (Solv-3)                          0.18                                 Solvent (Solv-7)                          0.18                                 Color Image Stabilizer (Cpd-7)            0.06                                 Second Layer (Color Mixing Preventing Layer):                                  Gelatin                                   0.99                                 Color Mixing Preventing Agent (Cpd-5)     0.08                                 Solvent (Solv-1)                          0.16                                 Solvent (Solv-4)                          0.08                                 Third Layer (Green-sensitive Emulsion Layer):                                  Silver Chlorobromide Emulsion             0.12                                 (1/3 (by mol as Ag) mixture of large grain size emulsion of large-size         cubic grains with                                                              mean grain size of 0.55 micron and coefficient of variation of grain size      distribution of                                                                0.10 and small grain size emulsion of small-size cubic grains with mean        grain size of 0.39                                                             micron and coefficient of variation of grain size distribution of 0.08;        both large-size and                                                            small-size grains locally had 0.8 mol % of AgBr on a part of the surface       of the grain)                                                                  Gelatin                                   1.24                                 Magenta Coupler (ExM)                     0.23                                 Color Image Stabilizer (Cpd-2)            0.03                                 Color Image Stabilizer (Cpd-3)            0.16                                 Color Image Stabilizer (Cpd-4)            0.02                                 Color Image Stabilizer (Cpd-9)            0.02                                 Solvent (Solv-2)                          0.40                                  Fourth Layer (Ultraviolet Absorbing Layer):                                   Gelatin                                   1.58                                 Ultraviolet Absorbent (UV-1)              0.47                                 Color Mixing Preventing Agent (Cpd-5)     0.05                                 Solvent (Solv-5)                          0.24                                 Fifth Layer (Red-sensitive Emulsion Layer):                                    Silver Chloride Emulsion (A)              0.23                                 Gelatin                                   1.34                                 Cyan Coupler (ExC)                        0.32                                 Color Image Stabilizer (Cpd-2)            0.03                                 Color Image Stabilizer (Cpd-4)            0.02                                 Color Image Stabilizer (Cpd-6)            0.18                                 Color Image Stabilizer (Cpd-7)            0.40                                 Color Image Stabilizer (Cpd-8)            0.05                                 Solvent (Solv-6)                          0.14                                 Sixth Layer (Ultraviolet Absorbing Layer):                                     Gelatin                                   0.53                                 Ultraviolet Absorbent (UV-1)              0.16                                 Color Mixing Preventing Agent (Cpd-5)     0.02                                 Solvent (Solv-5)                          0.08                                 Seventh Layer (Protective Layer):                                              Gelatin                                   1.33                                 Acryl-modified Copolymer of Polyvinyl Alcohol (modification degree                                                       0.17                                 Liquid Paraffin Compounds used above are as follows:                                                                     0.03                                 (ExY) Yellow Coupler:                                                          1/1 (by mol) mixture of the following compounds:                                ##STR21##                                                                      ##STR22##                                                                     and                                                                             ##STR23##                                                                     (ExM) Magenta Coupler:                                                          ##STR24##                                                                     (ExC) Cyan Coupler:                                                            1/1 (by mol) mixture of the following compounds:                                ##STR25##                                                                     and                                                                             ##STR26##                                                                     (Cpd-1) Color Image Stabilizer:                                                 ##STR27##                                                                     (Cpd-2) Color Image Stabilizer:                                                 ##STR28##                                                                     (Cpd-3) Color Image Stabilizer:                                                 ##STR29##                                                                     (Cpd-4) Color Image Stabilizer:                                                 ##STR30##                                                                     (Cpd-5) Color Mixing Preventing Agent:                                          ##STR31##                                                                     (Cpd-6) Color Image Stabilizer:                                                2/4/4 (by weight) mixture of the following compounds:                           ##STR32##                                                                      ##STR33##                                                                      ##STR34##                                                                     (Cpd-7) Color Image Stabilizer:                                                 ##STR35##                                                                     (Cpd-8) Color Image Stabilizer:                                                1/1 (by weight) mixture of the following compounds:                             ##STR36##                                                                     (Cpd-9) Color Image Stabilizer:                                                 ##STR37##                                                                     (Cpd-10) Antiseptic:                                                            ##STR38##                                                                     (Cpd-11) Antiseptic:                                                            ##STR39##                                                                     (UV-1) Ultraviolet Absorbent:                                                  4/2/4 (by weight) mixture of the following compounds:                           ##STR40##                                                                      ##STR41##                                                                      ##STR42##                                                                     (Solv-1) Solvent:                                                               ##STR43##                                                                     (Solv-2) Solvent:                                                              1/1 (by volume) mixture of the following compounds:                             ##STR44##                                                                      ##STR45##                                                                     (Solv-3) Solvent:                                                               ##STR46##                                                                     (Solv-4) Solvent:                                                               ##STR47##                                                                     (Solv-5) Solvent:                                                               ##STR48##                                                                     (Solv-6) Solvent:                                                              80/20 (by volume) mixture of the following compounds:                           ##STR49##                                                                      ##STR50##                                                                     (Solv-7) Solvent:                                                               ##STR51##                                                                     (S-2):                                                                          ##STR52##                                                                     __________________________________________________________________________

Samples Nos. 2 to 12 were prepared in the same manner as in preparation of Sample No. 1, except that the emulsion and the color sensitizing dye in the Fifth Layer (red-sensitive emulsion layer) were replaced by those shown in Table 1 below.

In order to examine the photographic properties of these samples, they were subjected to the following processing.

Each sample was wedgewise exposed for sensitometry for 1/10 second using a sensitometer (FWH Model manufactured by Fuji Photo Film Co., Ltd, with a light source having a color temperature of 3200° K.) with a red filter as inserted therebetween. The exposed samples were then processed with an automatic developing machine in accordance with the processing procedure described below, using the processing solutions also described below. The composition of the color developer was varied as shown in Table 1 below.

In addition, the indicated color developer was stored at room temperature for 2 weeks with an opening ratio (opening area/liquid capacity) of 0.02 cm⁻¹, and the samples were processed in the same manner with the stored (aged) color developer.

    ______________________________________                                         Processing Step Temperature                                                                               Time                                                ______________________________________                                         Color Development                                                                              35° C.                                                                             45 seconds                                          Bleach-Fixation 30 to 35° C.                                                                       45 seconds                                          Rinsing (1)     30 to 35° C.                                                                       20 seconds                                          Rinsing (2)     30 to 35° C.                                                                       20 seconds                                          Rinsing (3)     30 to 35° C.                                                                       20 seconds                                          Drying          70 to 80° C.                                                                       60 seconds                                          ______________________________________                                    

The compositions of the processing solutions used were as follows.

    ______________________________________                                         Color Development:                                                             Water                    800    ml                                             Ethylenediamine-N,N,N',N'-tetra-                                                                        1.5    g                                              methylenephosphonic Acid                                                       Potassium Bromide        See Table 1                                           Triethanolamine          8.0    g                                              Sodium Chloride          See Table 1                                           Potassium Carbonate      25     g                                              N-Ethyl-N-(β-methanesulfon-                                                                        5.0    g                                              amidoethyl)-3-methyl-4-aminoaniline                                            Sulfate                                                                        N,N-bis(Carboxymethyl)hydrazine                                                                         4.0    g                                              N,N-Di(sulfoethyl)hydroxylamine/1 Na                                                                    4.0    g                                              Brightening Agent (WHITEX 4B,                                                                           1.0    g                                              product of Sumitomo Chemical Co.)                                              Water to make            1000   ml                                             pH (25° C.)       10.05                                                 Bleach-Fixing Solution:                                                        Water                    400    ml                                             Ammonium Thiosulfate (700 g/l)                                                                          100    ml                                             Sodium Sulfite           17     g                                              Ammonium Ethylenediamine-                                                                               55     g                                              tetraacetato/Iron (III)                                                        Disodium Ethylenediaminetetraacetate                                                                    5      g                                              Ammonium Bromide         40     g                                              Water to make            1000   ml                                             pH (25° C.)       6.0                                                   Rinsing Solution:                                                              Ion-exchange Water (having a calcium content of 3 ppm                          or less and a magnesium content of 3 ppm or less).                             ______________________________________                                    

The cyan color density of each of the thus processed samples was measured and the characteristic curve of each sample was obtained.

To evaluate the fluctuation of photographic properties caused by processing with a fatigued color developer, the sensitivity fluctuation (ΔS) and the density fluctuation (ΔD) were determined. The sensitivity fluctuation is represented by the difference in the logarithmic value of the exposure amount necessary for a density higher than the fog density by 0.5. A positive value means desensitization due to fatigued developer occurred. Regarding the density fluctuation, the density obtained by an exposure amount higher than the exposure amount necessary for a density of (fog density+0.5) by 0.5 log E was determined for the fresh developer and for the fatigued developer, and the difference between the two values thus determined (one for the fresh developer, and the other for the fatigued developer) was obtained as the density fluctuation. A positive value for the density fluctuation obtained means that the sample as processed with fatigued developer was softened more than that processed with fresh developer. In addition, the fog density (D_(min)) of the sample as processed with fatigued developer was also determined. The results thus obtained are shown in Table 1 below.

                                      TABLE 1                                      __________________________________________________________________________     Composition of  Chloride Ion                                                                          Bromide Ion                                             Red-Sensitive Layer                                                                            in Developer                                                                          in Developer                                                     Color sensi-                                                                          Content                                                                               Content                                                 Sample                                                                             Emulsion                                                                            tizing dye                                                                            (mol/l)                                                                               (mol/l)                                                                               D.sub.min                                                                         ΔS                                                                          ΔD                                                                          Remarks                                 __________________________________________________________________________     1   A    S-1    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.11                                                                              0.10                                                                              0.12                                                                              Comparative                                                                    sample                                  2   A    I-3    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.11                                                                              0.05                                                                              0.05                                                                              Sample of                                                                      the Invention                           3   B    S-1    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.11                                                                              0.08                                                                              0.11                                                                              Comparative                                                                    sample                                  4   B    I-3    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.11                                                                              0.05                                                                              0.04                                                                              Sample of                                                                      the Invention                           5   C    S-1    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.14                                                                              0.15                                                                              Comparative                                                                    sample                                  6   C    I-3    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.12                                                                              0.13                                                                              Comparative                                                                    sample                                  7   D    S-1    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.08                                                                              0.11                                                                              Comparative                                                                    sample                                  7   D    S-1    7 × 10.sup.-3                                                                   1 × 10.sup.-4                                                                   0.14                                                                              0.09                                                                              0.12                                                                              Comparative                                                                    sample                                  7   D    S-1    3 × 10.sup.-1                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.10                                                                              0.18                                                                              Comparative                                                                    sample                                  7   D    S-1    6 × 10.sup.-2                                                                   0      0.17                                                                              0.06                                                                              0.11                                                                              Comparative                                                                    sample                                  7   D    S-1    6 × 10.sup.-2                                                                   2 × 10.sup.-3                                                                   0.10                                                                              0.08                                                                              0.16                                                                              Comparative                                                                    sample                                  8   D    S-2    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.07                                                                              0.12                                                                              Comparative                                                                    sample                                  9   D    I-3    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.03                                                                              0.03                                                                              Sample of                                                                      the Invention                           9   D    I-3    7 × 10.sup.-3                                                                   1 × 10.sup.-4                                                                   0.14                                                                              0.04                                                                              0.05                                                                              Comparative                                                                    sample                                  9   D    I-3    3 × 10.sup.-3                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.08                                                                              0.14                                                                              Comparative                                                                    sample                                  9   D    I-3    6 × 10.sup.-2                                                                   0      0.18                                                                              0.04                                                                              0.11                                                                              Comparative                                                                    sample                                  9   D    I-3    6 × 10.sup.-2                                                                   2 × 10.sup.-3                                                                   0.10                                                                              0.09                                                                              0.10                                                                              Comparative                                                                    sample                                  10  D    I-6    6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.03                                                                              0.04                                                                              Sample of                                                                      the Invention                           11  D    I-22   6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.03                                                                              0.05                                                                              Sample of                                                                      the Invention                           12  D    I-32   6 × 10.sup.-2                                                                   1 × 10.sup.-4                                                                   0.10                                                                              0.04                                                                              0.04                                                                              Sample of                                                                      the Invention                           __________________________________________________________________________      Regarding D.sub.min, ΔS and ΔD, smaller values indicate that       the variation of photographic properties is smaller in continuous              processing.                                                              

As is obvious from the results shown in Table 1 above, the comparative samples containing a color sensitizing agent outside the scope of the present invention showed a large fluctuation in photographic properties when processed with fatigued color developer. In contrast, the samples containing a color sensitizing agent of the present invention were free from fluctuation in photographic properties even when processed with fatigued color developer. The effect could not be obtained when the samples contained a high silver bromide emulsion. In addition, fog of the samples processed with fatigued color developer as well fluctuation of photographic properties of the samples processed with fatigued color developer could effectively be prevented only when the color developer had a chloride ion concentration and a bromide ion concentration both within the scope of the present invention.

EXAMPLE 2

32 g of a lime-processed gelatin was added to 1000 cc of distilled water and dissolved at 40° C., 1.6 g of sodium chloride was added thereto, and the temperature of the resulting solution was increased to 54° C. To the solution was added 1.7 cc of an aqueous 1% solution of N,N'-dimethylimidazolidine-2-thione. Next, a solution of 32.0 g of silver nitrate dissolved in 200 cc of distilled water and a solution of 11.0 g of sodium chloride dissolved in 200 cc of distilled water were added, with blending, to the previously prepared solution over a period of 14 minutes at 54° C. Further, a solution of 48.0 g of silver nitrate dissolved in 210 cc of distilled water and a solution of 16.5 g of sodium chloride dissolved in 210 cc of distilled water were added thereto, with stirring, over a period of 15 minutes at 54° C. Further, a solution of 80.0 g of silver nitrate dissolved in 350 cc of distilled water and a solution of 27.5 g of sodium chloride dissolved in 350 cc of distilled water were added thereto, with stirring, over a period of 25 minutes at 54° C. The resulting emulsion was desalted and washed with water at 40° C., 90.0 g of a lime-processed gelatin was added thereto, and sodium chloride and sodium hydroxide were added thereto whereby the pAg and pH of the emulsion were adjusted to 8.1 and 6.0, respectively. The emulsion was heated to 46° C., and 6×10⁻⁵ mol per mol of silver halide of red-sensitizing dye (S-1) was added thereto. An emulsion of ultra-fine silver bromide grains (having a grain size of 0.05 μm) was added thereto in an amount of 0.55 mol %, with respect to the silver chloride, of silver bromide, and the resulting emulsion blend was ripened for 25 minutes. Subsequently, this was optimally sulfur-sensitized with triethylthiourea at 46° C. The silver chlorobromide emulsion (having a silver bromide content of 0.55 mol %) thus obtained was designated Emulsion (E).

Emulsion (F) (silver chlorobromide emulsion) was prepared in the same manner as in preparation of Emulsion (E), except that the red-sensitizing dye was replaced by (I-3).

Emulsion (G) (silver chlorobromide emulsion) was prepared in the same manner as in preparation of Emulsion (F), except that 1.1×10⁻⁴ mol, per mol of silver bromide, of potassium hexachloroiridate(IV) was previously added to the emulsion of ultra-fine silver bromide grains to be added prior to sulfur sensitization and thereafter the resulting emulsion blend was optimally sulfur-sensitized in the same manner.

All three Emulsions (E) through (G) contained cubic grains having a mean grain size of 0.52 μm and a grain size distribution of 0.10. From the electromicrophotographs of Emulsions (E), (F) and (G), the cubic grains of each emulsion were found to have a shape with sharp corners. The X-ray diffraction analyses of these emulsions showed a weak diffraction in the part corresponding to the silver bromide content of from 10 mol % to 50 mol %. From these facts, these emulsions were determined to contain cubic silver chlorobromide grains having a silver bromide localized phase with a silver bromide content of from 10 mol % to 50 mol % on the corners of the cubic silver chloride grain (host grain), the localized phase having been grown by epitaxial growth.

Samples Nos. 13, 14 and 15 were prepared in the same manner as in preparation of Sample No. 1 of Example 1, except that only the emulsion in the Fifth Layer (red-sensitive layer) was replaced by an emulsion as shown in Table 2 below.

These samples were exposed in the same manner as in Example 1, and the exposed samples were then continuously processed with a processing machine in accordance with the processing procedure described below, using the processing solutions also described below, until the amount of the replenisher to the color developer tank became two times the capacity of the tank.

    ______________________________________                                         Processing Steps                                                               Processing                   Replenisher                                                                            Capacity                                  Steps    Temperature                                                                               Time     (*)     of Tank                                   ______________________________________                                         Color    35° C.                                                                             45 sec   161 ml  17 liters                                 Development                                                                    Bleach-  30 to 35° C.                                                                       45 sec   215 ml  17 liters                                 fixation                                                                       Rinsing (1)                                                                             30 to 35° C.                                                                       20 sec   --      10 liters                                 Rinsing (2)                                                                             30 to 35° C.                                                                       20 sec   --      10 liters                                 Rinsing (3)                                                                             30 to 35° C.                                                                       20 sec   350 ml  10 liters                                 Drying   70 to 80° C.                                                                       60 sec                                                     ______________________________________                                          (*) Amount of replenisher is per m.sup.2 of sample being processed.      

(Rinsing was effected by a three-tank counter-current system from rinsing tank (3) to rinsing tank (1).)

The processing solutions used in the above-mentioned steps had the following compositions.

    ______________________________________                                                          Tank                                                                           Solution  Replenisher                                         ______________________________________                                         Color developer                                                                Water              800      ml     800  ml                                     Ethylenediamine-N,N,N',N'-                                                                        1.5      g      2.0  g                                      tetramethylenephosphonic Acid                                                  Potassium Bromide  5 × 10.sup.-5                                                                     mol    --                                          Triethanolamine    8.0      g      12.0 g                                      Sodium Chloride    5 × 10.sup.-2                                                                     mol    --                                          Potassium Carbonate                                                                               25       g      25   g                                      N-ethyl-N-(β-methanesulfon-                                                                  5.0      g      7.0  g                                      amidoethyl)-3-methyl-                                                          4-aminoaniline Sulfate                                                         N,N-bis(Carboxymethyl)-                                                                           4.0      g      5.0  g                                      hydrazine                                                                      N,N-Di(sulfoethyl)hydroxyl-                                                                       4.0      g      5.0  g                                      amine/1 Na                                                                     Brightening Agent (WHITEX 4B,                                                                     1.0      g      2.0  g                                      product of Sumitomo                                                            Chemical Co.)                                                                  Water to make      1000     ml     1000 ml                                     pH (25° C.) 10.05           10.45                                       Bleach-fixing Solution:                                                        (Tank solution and replenisher were same.)                                     Water                      400    ml                                           Ammonium Thiosulfate (700 g/l)                                                                            100    ml                                           Sodium Sulfite             17     g                                            Ammonium Ethylenediamine tetraacetato/Iron (III)                                                          55     g                                            Disodium Ethylenediaminetetraacetate                                                                      5      g                                            Ammonium Bromide           40     g                                            Water to make              1000   ml                                           pH (25° C.)         6.0                                                 Rinsing Solution:                                                              (Tank solution and replenisher were same.)                                     Ion-exchange Water                                                             (having calcium content of 3 ppm or less and magnesium                         content of 3 ppm or less).                                                     ______________________________________                                    

For the purpose of evaluating the fluctuation of photographic properties arising due to continuous processing, the sensitivity fluctuation (ΔS) and the density fluctuation (ΔD) were determined. The sensitivity fluctuation is represented by the difference in the logarithmic value of the exposure amount necessary for a density higher than the fog density by 0.5 between the sample as processed at the start of the continuous processing and the sample as processed at the end of the continuous processing. A positive value means desensitization due to continuous processing occurred. Regarding the density fluctuation, the density value obtained by an exposure amount higher than the exposure amount necessary for a density of (fog density+0.5) by 0.5 log E was determined for the sample as processed at the start of the continuous processing and for the sample as processed at the end of the continuous processing, and the difference between the two values thus determined was considered the density fluctuation. The positive value of density fluctuation means that the sample as processed at the end of the continuous processing was softened more than that processed at the start of the continuous processing. In addition, the fog density (D_(min)) of the sample processed at the end of the continuous processing was also determined. The results thus obtained are shown in Table 2 below.

                  TABLE 2                                                          ______________________________________                                         Composition of Red-                                                            sensitive Layer                                                                               Color                                                                          Sensitizing                                                     Sample                                                                               Emulsion Dye       D.sub.min                                                                           ΔS                                                                            ΔD                                                                            Remarks                                ______________________________________                                         13    E        S-1       0.10 0.09 0.21 Comparative                                                                    sample                                 14    F        I-3       0.10 0.04 0.07 Sample of the                                                                  invention                              15    G        I-3       0.10 0.03 0.03 Sample of the                                                                  Invention                              ______________________________________                                    

Regarding Dmin, ΔS and ΔD, smaller values indicate that the fluctuation of the photographic properties is smaller in continuous processing.

As is obvious from the results in Table 2 above, the comparative samples containing a color sensitizing agent outside the scope of the present invention showed a large fluctuation in photographic properties in continuous processing. In contrast, the samples containing a color sensitizing agent of the present invention were free from fluctuation of photographic properties in continuous processing. In addition, fluctuation of photographic properties in continuous processing could be inhibited extremely effectively in the case of using an iridium compound-containing silver halide emulsion.

In accordance with the image forming method of the present invention, a high silver chloride photographic material may be processed well by rapid processing while retarding fog of the processed material. The material may also be processed well even with fatigued color developer and in continuous processing with marked reduction in fluctuation of the sensitivity and gradation of the processed material.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. 

What is claimed is:
 1. A method of forming a photographic image comprising imagewise exposing a silver halide color photographic material comprising a support having thereon a cyan color image forming layer, a magenta color image forming layer and a yellow color image forming layer, wherein the cyan color image forming layer in the photographic material contains silver halide emulsion grains having a silver chloride content of 95 mol % or more and containing substantially no silver iodide and contains a color sensitizing dye of the following general formula (I): ##STR53## wherein Z₂₃ and Z₂₄ independently represent an atomic group necessary for forming a heterocyclic nucleus selected from the group consisting of a benzothiazole nucleus, a benzoselenazole nucleus, a naphthothiazole nucleus and a naphthoselenazole nucleus, which may optionally be substituted by at least one substituent selected from the group consisting of a halogen atom, an alkyl group, an alkoxy group, an aryl group and a hydroxyl group, and two alkyl groups of the substituents, if any, may combine and form a ring; R₂₅ represents a hydrogen atom, an alkyl group or an aryl group;R₂₃ and R₂₄ independently represent a substituted or unsubstituted alkyl group; X₂₁ represents an ion; and n₂₁ represents 0 or 1, and color developing the exposed material with a color developer, wherein the color developer has a chloride ion content of from 3.5×10⁻² to 1.5×10⁻¹ mol/liter and a bromide ion content of from 1.5×10⁻⁵ to 1.0×10⁻³ mol/liter; wherein an iridium compound is contained in a silver bromide localized phase of the silver halide emulsion grains.
 2. The method of forming a photographic image as in claim 1, wherein the silver halide emulsion grains in the cyan color image forming layer of the photographic material contain a silver bromide localized phase in an amount of more than 10 mol % as silver bromide content in the localized phase.
 3. The method of forming a photographic image as in claim 1, wherein the iridium compound is contained in an amount of from 10⁻⁹ mol to 10⁻⁶ mol per mol of silver halide in the emulsion.
 4. The method of forming a photographic image as in claim 1, wherein the iridium compound is selected from the group consisting of hexachloroiridates(III) or (IV), hexamineiridates(III) or (IV), and trioxalatoiridates(III) or (IV).
 5. The method of forming a photographic image as in claim 1, wherein chloride ion content in the color developer is from 4×10⁻² to 1×10⁻¹ mol/liter.
 6. The method of forming a photographic image as in claim 1, wherein bromide ion content in the color developer is from 2×10⁻⁵ to 5×10⁻⁴ mol/liter. 